请为“统计Java程序中关键词的出现次数”提供一些测试源码

以下是一个Java程序的示例代码，用于统计关键词的出现次数：

import java.util.*;

public class KeywordCounter {
    public static void main(String[] args) {
        // Java keywords
        String[] keywords = {"abstract", "assert", "boolean", "break", "byte",
            "case", "catch", "char", "class", "const", "continue", "default",
            "do", "double", "else", "enum", "extends", "final", "finally",
            "float", "for", "if", "goto", "implements", "import", "instanceof",
            "int", "interface", "long", "native", "new", "package", "private",
            "protected", "public", "return", "short", "static", "strictfp",
            "super", "switch", "synchronized", "this", "throw", "throws",
            "transient", "try", "void", "volatile", "while"};

        // read Java source code from file or input stream
        String sourceCode = "public class HelloWorld {\n" +
            "    public static void main(String[] args) {\n" +
            "        System.out.println(\"Hello, World!\");\n" +
            "    }\n" +
            "}";

        // count keywords
        Map<String, Integer> keywordCount = new HashMap<>();
        for (String keyword : keywords) {
            keywordCount.put(keyword, 0);
        }
        String[] tokens = sourceCode.split("\\W+");
        for (String token : tokens) {
            if (Arrays.asList(keywords).contains(token)) {
                keywordCount.put(token, keywordCount.get(token) + 1);
            }
        }

        // print result
        for (String keyword : keywords) {
            System.out.println(keyword + ": " + keywordCount.get(keyword));
        }
    }
}

你可以根据自己的需要修改 `sourceCode` 变量的值，来测试不同的 Java 代码。